Chemical and physical analysis of lubricants is often used to provide information about the condition of the lubricant as well as the wear status of equipment in which the lubricant is used. Most often a lubricant sample is taken from the equipment in which it is used and is sent to the laboratory for analysis, where several analytical tests are performed to determine a number of chemical properties. Among the key analyses performed on engine oils are those for TBN and wear debris elements. Sending lubricant samples to a laboratory for analysis, however, does not provide the equipment operator any immediate information about the condition of the lubricant. This lapse in time can be critical to the operation of the equipment.
To help minimize the time required to obtained analytical results, various on-site or on-line devices have been proposed to monitor the condition of the lubricant as well as the wear status of the equipment being lubricated. Many of these devices include multiple analyzers. In this regard see, for example, U.S. Pat. No. 5,982,847; U.S. Pat. No. 6,561,010 B2; U.S. Pat. No. 5,987,976; US 2004/0123644 A1; U.S. Pat. No. 5,537,336; U.S. Pat. No. 6,779,505 B2; and PCT WO 01/36966 A2.
In U.S. Pat. No. 5,537,336 there is disclosed an oil test assembly that includes an infrared spectrometer (IR) and an emission spectrometer for measuring wear debris elements. TBN is one of the lube oil properties measured by IR.
Similarly, U.S. Pat. No. 6,561,010 B2 and PCT WO 01/36966 A2 disclose an apparatus for analyzing a machine fluid that also employs multiple sensors. In this instance at least one of the sensors is a viscosity sensor. Wear debris elements are measured by x-ray fluorescence (XRF) spectroscopy. TBN may be inferred by IR.
U.S. Pat. No. 6,779,505 B2 uses a similar method for controlling lube oil feed rates in certain diesel engine applications, where wear debris is measured by XRF and TBN is measured by IR.
U.S. Pat. No. 5,982,847 discloses a method for measuring wear metal in lubrication oils by XRF. Measurement of TBN is not taught.
US 2004/0123644 A1 discloses a method for measuring volatile components in an oil.
None of these devices measures TBN and wear debris elements with a single analyzer. Such a device is highly desired for many applications, since it decreases complexity and maintenance, resulting in increased reliability. A single on-line device would be highly advantageous for real-time analysis.